20-amp outlet, 15-amp circuit, builder BSing me???

The outlet/receptacle in my garage for my sprinkler timer is a single,
20-amp outlet. I went to replace it with a dual 20-amp outlet so I
could plug more than one thing at a time in. In doing so, I discovered
that this circuit is controlled by a 15-amp breaker (this circuit also
contains another 15-amp GFI outlet in my garage).
It's a new home, still under warranty. I reported this to the builder.
Two concerns:
1. Maybe it is supposed to be a 20-amp circuit and they tried to make
it look like one with the 20-amp outlet. All other add on outlets to
the house are 20-amp. The outlet for the sprinkler timer is an add on
since the front yard landscaping was an option. I don't think they'll
ever tell me for sure if that should have been a 20-amp circuit and
they forgot to put it in, so they piggy backed off of the exisiting
15-amp circuit in the garage.
2. Is it legal for them to put a 20-amp outlet on a 15-amp circuit? I
asked this question. The builder said "for the sprinkler timer, they
are allowed to use a single 20-amp outlet/receptable even though it is
a 15-amp circuit." What??? That doesn't make any sense.
Am I being BS'ed? I cannot get access to the NEC code book to research
this myself. My county uses the 2002 NEC.
Thanks in advance for any input.
Mike

Should be able to get a copy of the code somplace and look it up. If
they claim that it's OK ask them exactly where in the code, buecuas eI
bet they can't tell you. What size is the wire used for this curcuit?

There is a problem, but without knowing the wire size, it is hard to say
what.
If the wire is #14, the outlet must be 15a. This is potentially dangerous
because if you plugged a 20a load in, it could start a fire if the 15a
breaker didn't trip; though this is unlikely since the breaker should trip.
If the wire is #12 then the breaker should be 20a. This is harmless, but a
20a load (should you ever find one) will trip the breaker.
Possible they intended it as a 20a circuit, but when they added the 15a
GFCI, they changed the breaker to a 15a. What is the wire size?
BTW, unless the single receptacle is in a place where it will be permanently
used by a refrigerator (or similar) it must be GFCI protected. If you
change it, it must be to a GFCI outlet.

What size is the wiring? If it's 14-2, you've got the correct breaker. If
it's 12-2, you can swap the breaker out for a 20A. Just make sure the run is
100% 12-2 from end to end before making such a swap. If this guy was a hack,
you'll never know if he made a junction somewhere from 12-2 to 14-2 in the
middle for a myriad of reasons. Very unlikely that this was done, but unless
you can see it with your eyes, I wouldn't sleep well at night.
Putting a 20A outlet on a 15A circuit isn't going to cause any safety issues.
The worst thing that can happen is you keep tripping the breaker if you try to
use too much juice. This is a good thing and is protecting you like it should
be. Does it introduce all kinds of confusion? Yea, sure. But at least
you're still safe and won't burn the house down.
Unless you NEED 20A outlets, just live with the fact that 15A is more than
enough for every day use, unless this is for a work shop or other heavy
equipment. Look at the paperwork that came with your timer. I'm quite
confident it doesn't require a 20A circuit.
Whatever his intentions were is a different story....

My NEC book is old (1984) but it does say in Table 210-21(b)(3) that
15-amp circuits shall have a receptacle rating not over 15-amps. for
a 20-amp circuit, you can use 15 or 20 amp receptacles. The real
determining factor is the wire gauge they used. If it's 14, you have
a 15-amp circuit. If it's 12, it can handle 20-amps. The idiot who
wired our garage used one 15-amp circuit with 14-gauge wire to handle
the garage outlets, all outside outlets and a utility room off the
garage. My air compressor wouldn't even start. Fortunately, he did
put in a 20-amp circuit for the built-in vacuum so I can plug the air
compressor in there when I need it.

The simple answer to your question is yes the builder is BSing you. The
US NEC specifically limits the receptacles on a fifteen ampere circuit
to fifteen ampere pattern. The rating of the Over Current Protective
Device is what governs the ampacity of the circuit rather than the wire
size. The wire size could be increased to ten gage to compensate for
voltage drop but that would not make the circuit twenty ampere.
210.21 Outlet Devices.
Outlet devices shall have an ampere rating that is not less than the
load to be served and shall comply with 210.21(A) and (B).
(B) Receptacles.
(3) Receptacle Ratings. Where connected to a branch circuit supplying
two or more receptacles or outlets, receptacle ratings shall conform to
the values listed in Table 210.21(B)(3), or where larger than 50
amperes, the receptacle rating shall not be less than the branch-circuit
rating.
Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits
Circuit Rating (Amperes) Receptacle Rating (Amperes)
15 Not over 15
20 15 or 20
30 30
40 40 or 50
50 50
I cannot imagine how this could be more clear. A fifteen ampere circuit
may not have a receptacle that is more than fifteen ampere pattern.
Since these receptacles were add ons or extras they were probably done
without benefit of permit or inspection. You may want to suggest to the
builder that if it is not corrected you will call in the electrical
inspector.
--
Tom Horne

single outlets in cement floor area's are often exempt from having to be
GFI protected. Some AC motors trip GFI outlets when they kick on & off
so rather than have you reset the GFI often when the sump pump kicks
off, the electricians got the code to permit non-GFI outlet to be used for
single outlet plates for use of an appliance that is plugged into it on a
relatively permanent basis.
I think the normal single outlet sockets are 20 amp? I would hope the
electrician
ran thick enough wire for the 20 amp circuit to the outlet and just did not
install a 20 amp
circuit because the sprinkler did not require one.

I think the NEC says Garage needs to GFCI. No mentioning of whether
the floor is cement or other.

On the other hand, if it was a dedicated receptical, not ment to be
used for a cord and plug appliance(I'm guessing his sprinkler might
be), then there are exemptions about using a GFCI protected
receptacle.

Is it possible this is a singlex, 15a receptacle? It may be an innocent mistake
that a 15a singlex, non-gfci'd receptacle was supposed to be installed
specifically for a sprinkler timer, and a 20a singlex was mistakenly installed
as they're more common.

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